Some passages are infectious with her fascination for the colors (pigments) and the histories. However, there was a lot of fanciful "What if"-ing, when the facts were not available. Also, the huge chunks of history could have been broken down into something easier to digest. The section on lapiz lazuli in Afghanistan was such a terribly dry read.
Almost half a year later, finally finished reading this. Often found myself glossing over paragraphs, and had to take breaks to get my concentration back. Now and then my efforts would be rewarded with a dinner conversation-worthy fact. "Did you know that some sacred Jewish vestments are dyed with a pigment from un-kosher sources?" "Did you know that Victorian wallpaper had arsenic?" It's like sifting through so much river silt, to find the occasional shiny nugget. A little patience is required.
All in all, it certainly makes one pause before being able to answer the question, "So what's your favorite color?" I think out of all the histories presented here, my favorite would be the Red chapter, then section on gamboge, but probably because of its exposure on Radiolab.